The present invention relates to a novel epoxy resin containing a bisphenol-F.
Bisphenol type epoxy resins are conventionally produced by reacting a compound having at least one epoxy group and a bisphenol. The resins have been used in various application areas such as coatings, laminates, insulation materials, encapsulation and potting of electric/electronic devices, adhesives, construction materials, moldings and composites.
Recently, such epoxy resins have been required to meet higher physical, mechanical and chemical standards because of progress of the various technologies such as electric/electronic devices and coatings. Epoxy resins need improved physical properties such as flexibility and film properties, and improved chemical properties such as curability. Furthermore, epoxy resins need to have lower melt/solution viscosity to enable reduced volatile content and increased solid resin content when dissolved in a solvent.
Generally speaking, when the molecular weight of the epoxy resin is increased, physical properties such as flexibility and impact resistance, and chemical properties such as solvent resistance and corrosion resistance are improved, but the melt and/or solution viscosity of the epoxy resins increases and processability deteriorates.
Some improvement has been realized by incorporating bisphenol-F into the epoxy resin. Bisphenol-F epoxy resins have relatively low viscosity compared with bisphenol-A epoxy resins. For example, epoxy resin compositions based on bisphenol-F epoxy resin are disclosed in Japanese Kokai Patent Publications S[5]59-8767, H2-166114, H3-33169, H3-45620 and H3-76770. However, further improvements in viscosity and/or physical properties would be desirable.
It is an object of the present invention to provide an epoxy resin which has both low viscosity and good physical properties.